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185
Motion-based Segmentation and Contour-based Classification of Video Objects
, 2001
"... The segmentation of objects in video sequences constitutes a prerequisite for numerous applications ranging from computer vision tasks to second-generation video coding. ..."
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Cited by 12 (0 self)
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The segmentation of objects in video sequences constitutes a prerequisite for numerous applications ranging from computer vision tasks to second-generation video coding.
Efficient In-Network Adaptation of Encrypted H.264/SVC Content
, 2009
"... This paper addresses the efficient adaptation of encrypted scalable video content (H.264/SVC). RTP-based in-network adaptation schemes on a media aware network element (MANE) in an IPTV and VoD scenario are considered. Two basic alternatives to implement encryption and adaptation of H.264/SVC conten ..."
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Cited by 10 (5 self)
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This paper addresses the efficient adaptation of encrypted scalable video content (H.264/SVC). RTP-based in-network adaptation schemes on a media aware network element (MANE) in an IPTV and VoD scenario are considered. Two basic alternatives to implement encryption and adaptation of H.264/SVC content are investigated: (i) full, format-independent encryption making use of Secure RTP (SRTP); (ii) SVC-specific encryption that leaves the metadata relevant for adaptation (NAL unit headers) unencrypted. The SRTP-based scheme (i) is straightforward to deploy, but requires the MANE to be in the security context of the delivery, i.e., to be a trusted node. For adaptation, the content needs to be decrypted, scaled, and re-encrypted. The SVC-specific approach (ii) enables both full and selective encryption, e.g., of the base layer only. SVC-specific encryption is based on own previous work, which is substantially extended and detailed in this paper. The adaptation MANE can now be an untrusted node; adaptation becomes a low-complexity process, avoiding full decryption and re-encryption of the content. This paper presents the first experimental comparison of these two approaches and evaluates whether multimedia-specific encryption can lead to performance and application benefits. Potential security threats and security properties of the two approaches in the IPTV and VoD scenario are elementarily analyzed. In terms of runtime performance on the MANE our SVC-specific encryption scheme significantly outperforms the SRTP-based approach. SVC-specific encryption is also superior in terms of induced end-to-end delays. The performance can even be improved by selective application of the SVC-specific encryption scheme. The results indicate that efficient adaptation of SVC-encrypted content on low-end, untrusted network devices is feasible.
An Introduction to MPEG-4 Audio Lossless Coding
- Proc. IEEE ICASSP
, 2004
"... This convention paper has been reproduced from the author’s advance manuscript, without editing, corrections, or consideration by the Review Board. The AES takes no responsibility for the contents. Additional papers ..."
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Cited by 9 (3 self)
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This convention paper has been reproduced from the author’s advance manuscript, without editing, corrections, or consideration by the Review Board. The AES takes no responsibility for the contents. Additional papers
A tensor-driven active contour model for moving object segmentation
- In Proc. IEEE International Conference on Image Processing (ICIP), volume II
, 2001
"... In this paper we propose an approach to the segmentation of video objects based on motion cues. Motion analysis is performed by estimating local orientations in the spatiotemporal domain using the three-dimensional structure tensor. These estimates are integrated as an external force into an active ..."
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Cited by 9 (1 self)
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In this paper we propose an approach to the segmentation of video objects based on motion cues. Motion analysis is performed by estimating local orientations in the spatiotemporal domain using the three-dimensional structure tensor. These estimates are integrated as an external force into an active contour model, thus stopping the evolving curve when it reaches the moving object’s boundary. To enable simultaneous detection of several objects, we reformulate the tensor-based active contour model using the level-set technique. In addition, a contour refinement technique has been developed to better approximate the real boundary of the moving object. We provide promising experimental results calculated on real-world video sequences widely used within the computer vision community. 1.
A case for 3D streaming on peer-to-peer networks
- In Proceedings of Web3D ’06
, 2006
"... One of the most serious issues holding back the widespread of 3D contents on Internet has been their inaccessibility due to large data volume. Many compression and progressive transmission tech-niques, as well as format standards, have been proposed in recent years to make 3D streaming increasingly ..."
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Cited by 9 (3 self)
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One of the most serious issues holding back the widespread of 3D contents on Internet has been their inaccessibility due to large data volume. Many compression and progressive transmission tech-niques, as well as format standards, have been proposed in recent years to make 3D streaming increasingly viable for the efficient and accessible delivery of 3D contents. However, existing propos-als have yet to seriously address one of the most important issues in practical adoption – a system’s scalability in terms of the number of concurrent users. We argue that due to 3D contents ’ large data vol-ume and interactive nature, client-server architecture, with its inher-ently fixed resource availability and high cost, will not be suitable to support popular Internet-scale 3D streaming. On the other hand, peer-to-peer (P2P) architectures hold the promise of both scalabil-ity and affordability. In this position paper, we describe the po-tential promises and challenges in adapting 3D streaming to P2P networks, using multi-user networked virtual environment (NVE) as an example. We also propose Flowing LoD (FLoD), a scalable, distributed and fault-tolerant P2P 3D streaming mechanism, that is based on Voronoi-based Overlay Network (VON), a P2P overlay specifically designed for NVE applications.
Semantic-aware Link Layer Scheduling of MPEG-4 Video Streams in Wireless Systems
- In Proc. of Applications and Services in Wireless Networks (ASWN
, 2003
"... Delivering video streams to terminals via a wireless last hop is a challenging task due to the varying nature of the wireless link. While a common approach suggests to exploit the variations of the wireless channel, an alternative is to exploit characteristics of the video stream to improve the tran ..."
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Cited by 8 (8 self)
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Delivering video streams to terminals via a wireless last hop is a challenging task due to the varying nature of the wireless link. While a common approach suggests to exploit the variations of the wireless channel, an alternative is to exploit characteristics of the video stream to improve the transmission. In this paper we show how semantic stream variations of MPEG-4 coded video can be used to increase the number of terminals which can be supported in a wireless cell at a given minimum video quality. As example system we consider the performance of an OFDM system with different video sources. Simulations show that the number of supportable terminals can be increased on average by fifty percent.
MPEG-4 BIFS Streaming of Large Virtual Environments and their Animation on the Web
"... Although the Virtual Reality Modeling Language has made viewing 3D content on the web possible, remotely accessing large and complex 3D worlds requires a great deal of bandwidth. In the absence of such bandwidth users will suffer substantial latency in receiving the entire scene before they are able ..."
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Cited by 7 (0 self)
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Although the Virtual Reality Modeling Language has made viewing 3D content on the web possible, remotely accessing large and complex 3D worlds requires a great deal of bandwidth. In the absence of such bandwidth users will suffer substantial latency in receiving the entire scene before they are able to view and interact with it. Streaming the 3D content and displaying the parts currently available while allowing users to interact with and navigate through the world reduces the time users have to wait in order to become involved in the virtual scene and hence improves their experience. This paper presents the use of the MPEG-4 standard for streaming of 3D worlds and the corresponding animation over the web while allowing users navigation and manipulation of the content, as it becomes available.
NCL 2.0: integrating new concepts to XML modular languages
- In ACM DocEng’04
, 2004
"... This paper presents the main new features of Nested Context Language (NCL) version 2.0. NCL 2.0 is a modular and declarative hypermedia language, whose modules can be combined to other languages, such as SMIL, to provide new facilities. Among the NCL 2.0 new features, we can highlight the support fo ..."
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Cited by 7 (1 self)
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This paper presents the main new features of Nested Context Language (NCL) version 2.0. NCL 2.0 is a modular and declarative hypermedia language, whose modules can be combined to other languages, such as SMIL, to provide new facilities. Among the NCL 2.0 new features, we can highlight the support for handling hypermedia relations as first-class entities, through the definition of hypermedia connectors, and the possibility of specifying any semantics for a hypermedia composition, using the concept of composition templates. Another important goal of this paper is to describe a framework to facilitate the development of NCL parsing and processing tools. Based on this framework, the paper comments several implemented compilers, which allow, for instance, the conversion of NCL documents into SMIL specifications.
Adaptation of scalable multimedia documents
- In Proceeding of the ACM Symposium on Document Engineering
, 2008
"... Several scalable media codecs have been standardized in recent years to cope with heterogeneous usage conditions and to aim at always providing audio, video and image content in the best possible quality. Today, interactive multimedia presentations are becoming accessible on handheld terminals and f ..."
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Cited by 7 (2 self)
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Several scalable media codecs have been standardized in recent years to cope with heterogeneous usage conditions and to aim at always providing audio, video and image content in the best possible quality. Today, interactive multimedia presentations are becoming accessible on handheld terminals and face the same adaptation challenges as the media elements they present: quite diversified screen, memory and processing power capabilities. In this paper, we address the adaptation of multimedia documents by applying the concept of scalability to their presentation. The Scalable MSTI document model introduced in this paper has been designed with two main requirements in mind. First, the adaptation process must be simple to execute because it may be performed on limited terminals in broadcast scenarios. Second, the adaptation process must be simple to describe so that authored adaptation directives can be transported along with the document with a limited bandwidth overhead. The Scalable MSTI model achieves both objectives by specifying Spatial, Temporal and Interactive scalability axes on which incremental authoring can be performed to create progressive presentation layers. Our experiments are conducted on scalable multimedia documents designed for Digital Radio services on DMB channels using MPEG-4 BIFS and also for web services using XHTML, SVG, SMIL and Flash. A scalable image gallery is described throughout this article and illustrates the features offered by our document model in a rich multimedia example.
TranScaling: A Video Coding and Multicasting Framework for Wireless IP Multimedia Services
, 2001
"... The convergence of the Internet with new wireless and mobile networks is creating a whole new level of heterogeneity in multimedia communications. This increased level of heterogeneity emphasizes the need for scalable and adaptive video solutions both for coding and transmission purposes. ..."
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Cited by 6 (2 self)
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The convergence of the Internet with new wireless and mobile networks is creating a whole new level of heterogeneity in multimedia communications. This increased level of heterogeneity emphasizes the need for scalable and adaptive video solutions both for coding and transmission purposes.
